1. Field of the Invention
This invention relates to a hood structure for a vehicle and, in particular, to a hood structure suitable for use in hoods constructed of plastic.
2. Description of Related Art
Conventionally, the front hood of a vehicle has been formed of metal. For the purpose of reducing the weight of the vehicle, however, it is known to use a plastic hood structure in place of a conventional metal vehicle hood. Japanese Utility Model Application 60-165267 discloses one such plastic hood structure. The plastic hood structure of this publication is equipped with diagonal ribs forming a crisscrossed reinforcing frame on the whole inner surface thereof. Because of this reinforcing frame, the plastic hood structure has the same strength as that of a hood formed of iron, steel or similar metal or metal alloy. However, the plastic hood disclosed by this publication does have problems similar to those present in conventionally constructed metal hoods. Most significantly, in a head on car crash, the hood disclosed by the Japanese publication has a tendency to move in a rearward direction of the vehicle and break the front windshield.
To prevent the plastic hood from impacting upon and breaking the front windshield of the vehicle, the hood of the Japanese publication is equipped with a fold region extending transversely of the hood and located in the middle region of the hood. The impact of a head-on car crash breaks the hood at the fold region and thus, the hood bends or folds in this region. The bending of the hood at the fold region helps prevent the hood from moving further rearward, breaking the front windshield, and endangering vehicle occupants.
In the event the collision produces an abnormally high impact force, however, it is possible that the impact from the crash will not be absorbed by the hood at the fold. It is, therefore, possible that the hood will bend in additional places, such as the area immediately adjacent the front windshield. If this occurs, the windshield will be broken.